1. Field of the Invention
The present invention relates to a hard disk drive, and, more particularly, to an actuator locking apparatus for a hard disk drive, by which an actuator is locked so that a magnetic head can not escape from a parking zone of a hard disk when rotation of the hard disk stops.
2. Description of the Related Art
A hard disk drive (HDD) is an auxiliary memory device of a computer and reads out data stored on a magnetic disk or writes data on the magnetic disk using a magnetic head.
FIG. 1 is a plane view schematically illustrating a conventional hard disk drive. FIG. 2 is an exploded perspective view illustrating a conventional actuator, a conventional voice coil motor, and a conventional actuator locking apparatus. FIG. 3 is a side view illustrating the voice coil motor and the actuator locking apparatus of FIG. 2.
Referring to FIGS. 1 and 2, a conventional hard disk drive includes a magnetic disk (hard disk) 20 that is a recording medium on which data is recorded, a spindle motor 30 that is installed on a base plate 10 and rotates the disk 20, and an actuator 40 having a magnetic head 41 that writes data on the disk 20 and reproduces the data written on the disk 20.
In general, the disk 20, or a plurality of disks spaced apart a predetermined distance, is rotated by the spindle motor 30. Also, when the hard disk drive is turned off, a slider 42, in which the magnetic head 41 is mounted, is moved from a data zone 22 in which a magnetic signal is written and then seated on a parking zone 21, provided at an inner circumference of the disk 20.
The actuator 40 pivots around a pivot shaft 47 provided on the base plate 10. The actuator 40 includes an arm 46 having a pivot hole 48 formed in the middle of the arm 46 to receive the pivot shaft 47. A suspension 44, which supports the slider 42 to be elastically-biased toward the surface of the disk 20, is installed at one end of the arm 46.
The actuator 40 is actuated by a voice coil motor (VCM) 50. The VCM 50 includes a coil 56 that is coupled with the other end of the arm 46. A lower yoke 51 is installed a predetermined distance under the coil 56 and is fixedly attached to the base plate 10. An upper yoke 52 is installed above the coil 56 and is coupled with the lower yoke 51 by a screw 59. Magnets 53 and 54 are attached to the top surface of the lower yoke 51 and the bottom surface of the upper yoke 52, respectively, and each of the magnets 53 and 54 is spaced apart from the coil 56 by a predetermined distance.
In a conventional hard disk drive having the above-described structure, while data are written/reproduced on/from the disk 20, a lifting force caused by the rotation of the disk 20 and an elastic force generated by the suspension 44 act on the slider 42 to lift the slider 42 from the data zone 22 of the disk 20 to a height at which the lifting force and the elastic force balance each other. Thus, the magnetic head 41 mounted in the slider 42 is maintained at a constant interval from the rotating disk 20 and writes and reproduces data on and from the disk 20.
When the hard disk drive is turned off and the rotation of the disk 20 stops, because the lifting force by which the slider 42 is lifted diminishes, the slider 42 moves from the data zone 22 of the disk 20 such that the slider 42 does not contact the data zone 22, preventing damage to the data zone 22. That is, if the arm 46 of the actuator 40 is rotated by the VCM 50 so that the slider 42 is moved to the parking zone 21 of the disk 20 before the rotation of the disk 20 stops completely, the slider 42 is seated on the parking zone 21 when rotation of the disk 20 stops, and, thus, damage to the data zone 22 can be prevented.
Referring to FIGS. 2 and 3, a conventional actuator locking apparatus, which locks the actuator 40 so that the actuator 40 does not rotate after the slider 42 is seated on the parking zone 21 of the disk 20, is provided in the hard disk drive. That is, the actuator locking apparatus prevents the actuator 40 from rotating due to an external shock or vibration when the hard disk drive is turned off and prevents the magnetic head 41 from escaping from the parking zone 21 and moving to the data zone 22.
The conventional actuator locking apparatus is a magnetic latch-type locking apparatus that locks the actuator 40 using a magnetic force of the magnets 53 and 54 and includes a metal piece 65 installed at an end of the arm 46 and a contact part 66 in the upper yoke 52 to which the metal piece 65 adheres to by the magnetic force.
The installation structure of the metal piece 65 is as follows. A support part 62 protrudes from an end of the arm 46, and a hole 63 having a predetermined depth is formed in a horizontal direction on a surface of the support part 62. The support part 62 and the hole 63 are integrally formed with the arm 46 by plastic injection molding. A rubber damper 64 is securely fixed in the hole 63, and the metal piece 65 is attached to an end of the rubber damper 64. The rubber damper 64 attenuates a shock generated when the metal piece 65 that corresponds to the metal piece 65. Magnetic flux flows through the contact part 66 due to the magnets 53 and 54 respectively provided in the lower yoke 51 and the upper yoke 52. The metal piece 65 in the arm 46 is magnetically attracted to the contact part 66, due to the magnetic flux within the slot 67, thereby locking the actuator 40.
A plurality of disks are installed in the conventional hard disk drive to increase data storage capacity. However, recently, the surface recording density of disks has rapidly increased such that sufficient data can be stored using only one or two disks. In particular, a hard disk drive that writes data on only one side of a disk has recently been developed. In this case, an actuator having one magnetic head and one arm is needed, and a voice coil motor using one magnet installed only in an upper or a lower portion of a coil is generally used in such an actuator. Accordingly, the overall height of the actuator and the voice coil motor is reduced, and, thus, the hard disk drive can be miniaturized.
However, in a hard disk drive having a single magnet voice coil motor, the actuator is manufactured by press-processing a metallic material having a thickness smaller than a two-magnet voice coil motor. Thus, a hole in which a rubber damper is inserted cannot be formed at an end of an arm of the actuator, and the actuator locking apparatus having the structure as described above cannot be used. As a result, the hard disk drive with the single magnet voice coil motor requires an actuator locking apparatus having a new structure.